I am crawling SP2010 content in SP2016.
All my contents are getting crawled successfully (some items are getting crawled multiple time with different crawl id, I think this is another issue).
But they are not returning all results. Even many results missing when we are checking with search service account. In same time all SP2016 contents are getting crawled and giving all results.
Can you please help?
Ideally all results should show up, how did you made your queries?
you can search with "*" which will give all the results and you can get the count.
since you are saying the items crawled successfully, it might be due to permissions issue , did you check the service account is having the same permission for all the items? or whether permission has been stopped inheriting?
Please check the crawl logs. Alternatively you can use fiddler to see if the items are successfully crawled or not .
Please check @MatthewMcDermott 's search troubleshooting with Fiddler link
